Steel wire geometry optical measuring device for orthodontic bender calibration

Abstract

The utility model discloses a kind of steel wire geometric feature optical measuring devices for orthodontic bending machine calibration, belong to dental instrument manufacturing and machine vision measurement technical field.The device includes imaging module, scale module, light source module and processing module.The scale module is transparent base, dark high-contrast scale pattern is equipped on it, and it is installed on measurement plane by detachable positioning structure;The light source module is uniform area light source, is provided on the back of scale module, provides back light illumination;The imaging module includes image capture device, its optical axis is perpendicular to measurement plane;The processing module is connected with image capture device communication, for establishing two-dimensional mapping relationship of pixel coordinate to physical coordinate and calculating the actual geometric characteristic quantity of steel wire.The utility model is through the integration structure design of transparent scale and uniform backlight, so that steel wire and scale line present consistent edge optical characteristics in image, effectively eliminate the imaging error of inhomogeneous material same plane, applicable to the high-precision optical measurement of orthodontic steel wire bending.

Description

Technical Field

[0001] This utility model relates to the fields of dental instrument manufacturing and machine vision measurement technology, specifically to an optical measurement device for the geometric features of wire used in orthodontic bending machine calibration, which is particularly suitable for high-precision optical measurement of wire components such as orthodontic retainers and removable orthodontic appliances. Background Technology

[0002] In the manufacturing process of orthodontic retainers or removable aligners, medical wires often need to be bent into complex three-dimensional shapes. To ensure forming accuracy, high-precision geometric measurements of the bent wires are required. Current technologies typically employ imaging measurements by placing a metal ruler on the same plane as the wire. This ruler is usually a separate metal body, requiring frequent handling and resulting in poor installation repeatability. Furthermore, because its reflective properties differ from the wire's, their edge responses in the image are inconsistent, introducing systematic imaging errors. These errors manifest as edge detection deviations and inconsistent grayscale transitions, affecting the measurement accuracy of geometric parameters such as angles and curvature. In addition, existing rulers are usually fixed or require auxiliary positioning tools, making them cumbersome and unsuitable for rapid calibration and batch measurement scenarios. Utility Model Content

[0003] The purpose of this invention is to provide an optical measurement device for the geometric features of steel wire used in orthodontic bending machine calibration. By adopting a transparent base scale, a detachable positioning structure and a uniform backlight integrated design, the steel wire and the scale lines present consistent edge optical characteristics in the image, fundamentally eliminating imaging errors caused by differences in reflection from heterogeneous materials, and improving the ease of installation and measurement repeatability of the device, thereby achieving high-precision and efficient measurement of the geometric features of steel wire.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: An optical measuring device for the geometric characteristics of steel wire used in orthodontic bending machine calibration includes an imaging module, a scale module, a light source module, and a processing module.

[0005] The imaging module includes an image capture device and a horizontal measuring plane disposed below it, the measuring plane being used to support the bent steel wire to be measured and the scale module.

[0006] The scale module is made of a transparent base with a dark, high-contrast scale pattern on its surface or inside. The scale module is installed at a designated position on the measuring plane by a detachable positioning structure, which includes at least one of a snap-fit, a magnetic attraction, or a positioning pin, to ensure that the installation repeatability is better than ±0.1mm.

[0007] The light source module is a uniform surface light source, which is located on the back of the ruler module and is used to provide uniform backlight illumination to the ruler module and the steel wire located in front of it.

[0008] The processing module is communicatively connected to the image capture device and is used to perform image acquisition, image processing, establish a two-dimensional mapping relationship from pixel coordinates to physical coordinates, and calculate the actual geometric features of the steel wire based on the mapping relationship.

[0009] Furthermore, the optical axis of the image capture device is perpendicular to the measurement plane, and its field of view completely covers the area where the scale module and the steel wire are located.

[0010] Furthermore, the light source module is an LED array surface light source with a light intensity uniformity of not less than 90% and a color temperature range of 5000K-6500K. It is the only active lighting source in the system and has no lateral auxiliary light sources.

[0011] Furthermore, the transparent substrate of the scale module is made of acrylic or glass, and its light transmittance is not less than 85%.

[0012] Furthermore, the scale pattern is a black scale line with a line width of 0.05mm to 0.2mm, and not greater than 1 / 2 of the diameter of the steel wire to be measured.

[0013] Furthermore, the measuring plane is provided with grooves, bosses or magnetic arrays corresponding to the scale module to achieve rapid positioning and installation.

[0014] Furthermore, the processing module includes a storage unit and an image processing unit. The storage unit is used to store the two-dimensional mapping relationship obtained by the ruler module calibration, supporting a one-time calibration and multiple measurement working mode. The image processing unit is used to execute an edge detection algorithm to identify the edge contours of the steel wire and the scale line.

[0015] Furthermore, the surface of the measuring plane is made of black or dark-colored non-reflective material with a reflectivity of less than 5%, effectively suppressing ambient light interference.

[0016] Furthermore, the scale pattern is located on the side of the transparent substrate facing the light source module to ensure uniform backlight transmission and avoid uneven light transmission.

[0017] The workflow of this utility model is as follows: In calibration mode, the scale module is installed at a designated position on the measurement plane, uniform backlight is turned on, the image capture device acquires a calibration image containing only the scale module, and the processing module establishes and stores a precise two-dimensional mapping relationship between pixel coordinates and physical coordinates based on the known physical spacing of the scale lines.

[0018] In measurement mode, if the scale module is removed or the steel wire is placed on the measurement plane, the system calls the stored mapping relationship to perform edge recognition and coordinate transformation on the acquired steel wire image, and calculates the actual geometric features of the steel wire, such as the distance between the endpoints, bending angle, radius of curvature, etc.

[0019] The beneficial effects of this utility model are as follows: 1. High structural integration and convenient installation: It adopts an integrated design of transparent scale and detachable positioning structure, which can be installed quickly and has good repeatability, making it suitable for rapid calibration in industrial fields.

[0020] 2. Good imaging consistency and low system error: By combining uniform backlighting with a transparent substrate, the steel wire and the scale lines present a consistent silhouette, effectively eliminating imaging errors caused by heterogeneous materials.

[0021] 3. High efficiency: Supports "one-time calibration, multiple measurements" mode, which greatly improves testing efficiency and is suitable for mass production.

[0022] 4. High compatibility: The compact structure allows for direct integration into existing bending machine systems without significant equipment modifications.

[0023] This invention is particularly applicable to high-precision optical measurement and calibration in the manufacturing process of precision wire components such as orthodontic retainers and removable orthodontic appliances, providing reliable structured technical support for intelligent manufacturing of dental instruments. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the optical measuring device of this utility model; Figure 2 This is a schematic diagram of the front structure of the scale module; Figure 3 This is a schematic diagram showing the installation positions of the measuring plane and scale module; Figure 4 This is a schematic diagram of the optical path and imaging principle; Figure 5 A partially enlarged schematic diagram of the mounting structure of the detachable scale module; Figure 6 This is a schematic diagram of the working modes, including calibration and measurement modes.

[0025] Figure label: 1. Imaging module; 2. Scale module; 3. Light source module; 4. Processing module; 5. Steel wire; 11. Image capturing device; 12. Measuring plane; 21. Transparent substrate; 22. Scale pattern. Detailed Implementation

[0026] The specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0027] like Figure 1As shown, the optical measuring device of this utility model includes an imaging module 1, a scale module 2, a light source module 3, and a processing module 4. The imaging module 1 includes an image capture device 11 and a measuring plane 12. The measuring plane 12 is used to place the steel wire 5 to be measured and the scale module 2.

[0028] The surface of the measuring plane 12 is preferably made of black matte material with a reflectivity of less than 5% to effectively reduce ambient light reflection interference.

[0029] like Figure 2 As shown, the scale module 2 consists of a transparent substrate 21 and a dark-colored scale pattern 22 disposed thereon. The transparent substrate 21 can be made of acrylic or glass, with a light transmittance of not less than 85%. The scale pattern 22 is a black high-contrast line, which can be made by laser etching or screen printing. Its line width is preferably 0.05mm to 0.2mm, and not greater than 1 / 2 of the diameter of the steel wire 5 to be measured, to ensure edge detection accuracy. The scale module 2 can be detachably installed at a designated position on the measuring plane 12 by means of a snap, magnetic attraction, or positioning pin. Figure 3 , Figure 5 The measuring plane 12 is equipped with corresponding positioning structures, such as grooves, bosses or magnetic arrays, to ensure that the installation repeatability is better than ±0.1mm.

[0030] like Figure 5 As shown, the scale module 2 and the measuring plane 12 are connected by a plug-in or magnetic connection, which can be quickly disassembled and assembled, and facilitates the switching of calibration and measurement modes.

[0031] The light source module 3 is a uniform LED surface light source, located on the back of the scale module 2. Its light intensity uniformity is no less than 90%, its color temperature range is 5000K to 6500K, and its brightness is adjustable. This light source provides uniform backlighting for the steel wire 5 and the scale module 2, causing both to appear as dark silhouettes in the image with consistent edge optical characteristics. This light source module is the only active illumination source in the system, and there are no obstructions between the scale module and the measuring plane.

[0032] The scale pattern 22 is located on the side of the transparent substrate 21 facing the light source module 3 to ensure uniform backlight transmission and avoid uneven light transmission caused by the position of the pattern.

[0033] like Figure 4 As shown, the uniform backlight emitted by the light source module 3 passes through the scale module 2 and the steel wire 5 in sequence, and the silhouette image is captured by the image capture device 11 and transmitted to the processing module 4 for processing.

[0034] The optical axis of the image capture device 11 (such as an industrial camera) is perpendicular to the measurement plane 12, and its lens field of view is calibrated to ensure that it can completely cover the effective scale area of ​​the scale module 2 and the entire measurement area where the steel wire 5 may be placed.

[0035] The processing module 4 is communicatively connected to the image capture device 11 and has a built-in storage unit that can store the two-dimensional mapping relationship between pixel coordinates and physical coordinates obtained by the scale module 2. The image processing unit has a built-in image processing program that specifically performs the following steps: First, the acquired image is preprocessed (e.g., noise reduction and contrast enhancement). Then, an edge detection algorithm (e.g., the Canny operator) is used to identify the edges of the scale lines 22 and the steel wire 5. Based on the scale line edges with known physical spacing, a precise mapping relationship between the image pixel coordinates and the world physical coordinates is established. Finally, using this mapping relationship, the pixel coordinates of the steel wire edges are converted into physical coordinates, and the actual geometric features such as the centerline, bending angle, and radius of curvature of the steel wire are calculated.

[0036] This utility model supports an efficient working mode of "one calibration, multiple measurements" (such as...). Figure 6 The specific process is as follows: In calibration mode, only the scale module 2 is installed at the designated position on the measurement plane 12, the light source module 3 is turned on, the image capture device 11 acquires the scale image, and the processing module 4 automatically calculates and stores the mapping relationship between pixel coordinates and physical coordinates; in measurement mode, the scale module 2 is removed (or left in its original position), the steel wire 5 to be measured is placed on the measurement plane 12, and the system automatically calls the stored mapping relationship to quickly calculate its geometric feature quantities based on the steel wire image. In this mode, the system can complete multiple measurements under the same lighting conditions, significantly improving efficiency, and experimental calibration ensures that ambient light interference is below the set threshold (usually ≤5% illuminance change).

[0037] This invention integrates a transparent scale, a detachable positioning structure, and uniform backlighting into a single design. Combined with a high-contrast scale, a low-reflection measurement plane, and a precise image processing algorithm, it effectively eliminates imaging errors caused by differences in material reflection. The structure is simple and easy to install, making it suitable for high-precision calibration and testing of orthodontic bending machines.

Claims

1. An optical measuring device for the geometric characteristics of steel wire used in orthodontic bending machine calibration, characterized in that, include: The imaging module includes an image capture device and a horizontal measuring plane for supporting the steel wire to be measured and the scale module; A scale module, consisting of a transparent substrate, has a dark, high-contrast scale pattern on its surface or inside. The scale module is detachably mounted at a designated position on the measuring plane. The light source module is a uniform surface light source, which is located on the back of the scale module and is used to provide backlight to the scale module and the steel wire located in front of it; The processing module is communicatively connected to the image capture device and is used to perform image processing, establish a two-dimensional mapping relationship from pixel coordinates to physical coordinates, and calculate the actual geometric features of the steel wire. The ruler module and the steel wire are imaged under the same uniform backlight, resulting in consistent edge optical characteristics in the image.

2. The optical measuring device according to claim 1, characterized in that, The light source module is an LED array surface light source with a light intensity uniformity of not less than 90%.

3. The optical measuring device according to claim 1, characterized in that, The optical axis of the image capture device is perpendicular to the measurement plane, and its field of view completely covers the area where the scale module and the steel wire are located.

4. The optical measuring device according to claim 1, characterized in that, The transparent substrate of the scale module is made of acrylic or glass, and its light transmittance is not less than 85%.

5. The optical measuring device according to claim 1, characterized in that, The line width of the scale diagram is 0.05 mm to 0.2 mm.

6. The optical measuring device according to claim 1, characterized in that, The measuring plane is provided with a positioning structure for fixing the installation position of the scale module. The positioning structure includes a buckle, a magnetic attraction, or a positioning pin.

7. The optical measuring device according to claim 1, characterized in that, The processing module includes a storage unit for storing the two-dimensional mapping relationship obtained by the scale module, and supports a one-time calibration and multiple measurement mode.

8. The optical measuring device according to claim 1, characterized in that, The processing module also includes an image processing unit for executing an edge detection algorithm to identify the edges of the wire and the scale lines.

9. The optical measuring device according to claim 1, characterized in that, The surface of the measuring plane is made of black or dark-colored non-reflective material.

10. The optical measuring device according to claim 1, characterized in that, The scale pattern is located on the side of the transparent substrate facing the light source module.

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